1. Field of the Invention
This invention relates to logic for handling calls, and especially for routing calls, in a communication system.
2. Description of the Related Art
In modern telecommunications networks, for instance UMTS (universal mobile telecommunication system) networks, an individual subscriber may have a plurality of terminals that are registered to a single network. For instance, the subscriber may have a mobile phone, a home phone, an answering machine and an office phone. When a call is made to the subscriber there is a need for the network to route the call to the appropriate terminal. The network could direct the call to each of the terminals in turn; if there is no answer at one of the terminals then the call can be directed to the next terminal until an answer is had.
Depending on the subscriber's circumstances when the call is made he may prefer the call to be directed to a certain one of the terminals. For example, if the subscriber is at home his home phone may be his preferred means of answering the call; if he is travelling to the office his mobile phone may be preferred; and in the office his office phone may be preferred. Each time the user's preference changes he could send a message to the network to inform the network which of his terminals is now his preferred means of answering calls. However, this would be highly inconvenient for the user since he might frequently have to send such messages.
The subscriber could program the network with a static preset scheme defining the order in which to route an incoming call to the user's terminals. The call could be routed to the terminals one-by-one in that order until it is answered. However, if several terminals are tried unsuccessfully in this way then a considerable amount of time might elapse before the call is routed to the right terminal. This delays the completion of the call, and the calling party might even hang up if the delay is too long.
There is therefore a need for an improved means of determining which of a user's terminals to route calls to.